3D audio collectively refers to a series of signal processing, transmitting, coding, and reproducing technologies which provide another axis corresponding to a height direction to a sound scene on a horizontal surface (2D) which is provided from surrounding audio of the related art to provide sound having presence in a three dimensional space. Specifically, in order to provide 3D audio, a larger number of speakers need to be used as compared than the related art or a rendering technique which forms a sound image in a virtual position where no speaker is provided even though a small number of speakers are used is required.
The 3D audio may be an audio solution corresponding to an ultra high definition TV (UHDTV) and is expected to be used in various fields and devices. There are channel-based signals and object-based signals as a sound source which is provided to the 3D audio. In addition, there may be a sound source in which the channel-based signals and the object-based signals are mixed and thus a user may have a new type of listening experience.
On the other hand, higher order ambisonics (HOA) may be used as a technique for providing scene-based immersive sound. The HOA is able to reproduce an entire audio scene in a compact and optimal state, thus providing high quality three-dimensional sound. The HOA technique may be useful in virtual reality (VR) where it is important to provide an immersive sound. However, while the HOA has an advantage of reproducing the entire audio scene, it has a disadvantage in that the performance of accurately representing positions of individual sound objects within an audio scene is deteriorated.